J. Craig Venter and Archbishop Desmond Tutu come from vastly different worlds, but the men have at least one thing in common: They are among the tiny number of people who have had their genome sequenced.

The San Diego biologist and the Nobel laureate are spending time together in La Jolla this week to mark the 10th anniversary of the first mapping of the entire human genome, a historic feat accomplished by a team of researchers led by Venter.

“We put together one of the most amazing teams that made the impossible possible,” Venter said Monday night at a black-tie dinner at the Scripps Forum that served as a reunion for the genomics pioneers.

Tutu, who also spoke at the dinner, made his own genetic history by becoming one of the first Africans to have his DNA sequenced. The results, along with the genetic map of a Namibian bushman, were published last February in the scientific journal Nature.

The retired Anglican archbishop’s personal physician and two scientific advisers told him not to participate in the study out of fear that his DNA map might reveal potentially embarrassing secrets that otherwise would remain hidden away in his cells.

“If it happens it happens,” Tutu recalled telling them. “I said, ‘You say no, but I say yes.’ The benefits far outweighed what could happen to one little man.”

Tutu and the researchers, including Vanessa Hayes who now is with the J. Craig Venter Institute in Torrey Pines, also faced pressure from many blacks in South African who remembered the time before the fall of apartheid when corrupted science was sometimes used as a tool to justify racism and discrimination.

But nothing wavered the archbishop’s confidence that genomics would one day help explain why people of African descent face higher risks for developing prostate cancer and certain other diseases.

Like many other Africans, Tutu has suffered from tuberculosis, polio and prostate cancer, which have all been linked to genetic variations that increase a risk of developing the diseases.

After successfully fighting prostate cancer in the late 1990s, the disease reappeared in Tutu.

“Now, I’m walking around with prostate cancer,” said the archbishop, who dreamed of becoming a physician as a child. “I’m on hormonal treatment.”

By studying the DNA variations tied to diseases, researchers can better understand the biology of the illnesses, identify people who need more frequent monitoring and develop personalized medicines specifically for those with higher genetic risk factors.

“Prostate cancer is a scourge,” Tutu said. “It is a great privilege to be asked to be part of an undertaking that may bring so much relief to so many people.

“I would hope that other people would be ready to come forward and have their own genome sequenced,” he said.

Much of the evening in La Jolla was spent reminiscing about the heady days in the late 1990s when Venter put together a renegade group of scientists, with $300 million in funding from Applied Biosystems, to compete against the federal government’s human genome sequencing effort that had made little progress since its creation in 1990.

Venter took the money from the company that would later become a part of Carlsbad-based Life Technologies and created Celera in Rockville, Md.

The task seemed impossible to many people, including some recruited by Venter to work on the project.

“I remember being in that empty building in Rockville,” said Gene Myers, a mathematician who was charged with creating the mind bending algorithm needed to splice together bits of genetic code like the world’s biggest jigsaw puzzle.

“It was about 15 people with rented furniture, saying, ‘How are we going to do this,’ ” he said. “It was gut-wrenching at times.”

Hamilton Smith, another team member who won a Nobel Prize in 1978 for discovering special special enzymes used to cut strands of DNA into pieces, had his own doubts.

“The magnitude of the problem can be visualized if you think of shredding the 30 volumes of the Encyclopaedia Britannica and putting it back together,” he told the dinner crowd.

Despite the challenges, the Celera team completed its task within nine months.

“It was absolutely a team effort,” Venter said. “If any one part failed, we all failed.”

As the cost of sequencing has plummeted over the last decade, genomics has permeated the worlds of medicine, food production and biofuels.

But the nascent field still faces some big challenges. The cost of sequencing remains too high to make the test practical for most people. Scientists haven’t yet figured out how to interpret most of the genetic data. It’s unclear how genes, lifestyles and the environment interact to influence health.

And ethical questions remain about how best to use the information. Is it worth learning about a genetic risk for a deadly disease, such as Alzheimer’s, if nothing can be done to stop it? Will insurers or employers misuse the data? Should humans use the technology to create new types of life?

Some of those issues will be addressed today at a Nature-sponsored conference in La Jolla focusing on some of the latest research in genomics and the future of the science.

Life Technologies Chief Executive Greg Lucier summed up the outlook of many in the crowd at the Monday night dinner in remarks that closed the evening.

“We have come an extraordinarily long way in an extraordinarily short time,” he said. “You ain’t seen nothing yet.”